<template>
  <header class="header">
    <h1>todos</h1>
    <input id="toggle-all" class="toggle-all" type="checkbox" >
    <label for="toggle-all"></label>
    <input
      class="new-todo"
      placeholder="输入任务名称-回车确认"
      autofocus
      @keydown.enter="downFn"
      v-model="task"
    />
  </header>
</template>

<script>
export default {
 data() {
  return {
    task: '',
  }
 },
 methods: {
  downFn() {
    if (this.task.trim() === '') {
      alert('输入内容不可为空')
      return
    }
    this.$emit('add', this.task)
    this.task = ''
  }
 }
}
</script>